Fire control mechanism



Feb. l2, 1957 w. R, KuNz l FIRE CONTROL MECHANISM s sheetsQsheet 1 FiledOct. 14, 1954 Y l IN VEN TOR. \/\/l1111:lm f H KUNZ W/////////\\\\\\V\\\\\\\\\\\ W m. X

Arroz/wif? Feb. 12, 1957 w. R. KuNz .2,780,955

' FIRE CONTROLVMECHANISM I Filed Oct..4 14, 1954 ,3 Sheets-Sheet 2 Vll/s\\\\\\\\\\\\\\\\\\\\\\\ INVENTOR. A

William H KUNZ HTTONE YS Feb. 12, 1957 w. R. KUNZ FIRE CONTROL.MECHANISM v 5 Sheets-Sheet 3 Filed 0G11. 14, 1954 r AWignl'mm Y HTTO/VEYz,7s0,96s FIRE CONTROL MECHANISM William R. Kunz, Springfield, Mass.,assignor to the United States of America as represented by the Secretaryof the Army Application ctober 14, 1954, Serial No. 462,405

6 Claims. (Cl. 89--154) (Granted under Title 35, U. S. Code (1952), sec.266) The invention described herein may be manufactured and used by orfor the Goverment for governmental purposes Without the payment of anyroyalty thereon.

This invention relates to trigger mechanisms for semiautomatic firearmsand more particularly to trigger mechanisms of in-line operation.

lt is an object of this invention to provide a trigger mechanism whereinthe Sear is released by a short trigger pull.

It is another object of this invention to provide a trigger mechanismfor semi-automatic firearms wherein the hammer is positively reengagedby the sear when recoiled to cock position.

It is a further object of this invention to provide a trigger mechanismfor semi-automatic irearms which is rugged in construction and positivein operation.

The specific nature of the invention as well as other objects andadvantages thereof will clearly appear from a description of a preferredembodiment as shown in the accompanying drawings in which: I

Fig. 1 is a longitudinal cross-sectional view of the trigger mechanismof this invention showing the ham mer engaged in cock position by thesear;

Fig. 2 is a view similar to Fig. l but showing the sear retracted torelease the hammer; v

Fig. 3 is a view similar` to Figs. l and 2 but showing the actuatorblock released from the sea-r carrier by the hammer during movement tore position;

States Patent Y 2 20. Such safety is provided with a radially projectinglug portion 36 which is rotatable into engagement with the forwardvertical wall 38 of cutaway portion 34 when mounting pin 18 is rotatedby a handle 37 attached thereto to safe position.

A compressible coil spring 39 bears against the rear end of actuatorblock 24 to urge such actuator block against sear carrier 24. Theforward movement of sear carrier 26 is stopped by a transverse pin 40mounted through channel member 14 and receiver 12. Actuator block 24 isarranged to be pulled rearwardly by a lanyard v42 attached thereto, suchrearward movement being controlled by safety which, when rotated to safeposition, lug` 36 thereon engages wall 38 to hold the actuatorV blockimmovable against ,sear carrier 26 and permits limited reciprocalmovement of the sear carrier and actuator block when such lug is rotatedout of engagement with such wall when the safety is moved to olfposition. Y

view showing the sear partly pivoted by theV hammer' to unlatch position'during movement'ther'eof to cockposition; v p t Fig. 5 is a fragmentarylongitudinal cross-sectional view lshowing the safety device in safeposition; and

AFig. 6 is a perspective exploded View of the trigger mechanism of thisinvention.

Shown in the figures is a rearm receiver 12 and a substantially`U-shaped channel member 14 removably mounted therein by means of aretaining pin 16 and a mounting pin 18 which also serves as a bearingfor a safety 20 linked thereto for rotational movement between a safeand an 0E position. A hammer 22 is mountedpforwardly of channel member14 'in receiver `12 for pivotalmovement between a rearward cock positionand an upward re position and is arranged to be vpivoted to cockposition by recoil of the firearm bolt (not shown).V A springl biaseshammer 22 from cock to lire position. Y

Mounted for slidable movement in channel member 14 is an actuator block24 and a sear carrier 26 for wa-rdly thereof. Suchsear carrier andactuator block are, provided with longitudinal tongue portions, 28V and30 respectively, which ,protrude from the sides there of for slidableengagement with a pair of longitudinal grooves 32 which extend along theinsides of-th'e verti-` calwalls of channel member 14. The upper rearportion of actuator block 24 is cutaway to `form a right anglecross-section,"as noted at 34, for receiving safety Provided in thefront end of actuator block 24 is a vertical channel 44 in which aconnector member 48 is mounted for pivotal movement on a transverse pin46. Such connector member includes a forwardly extending hook portion 49which is receivable by a transverse groove 50 in the'top side of searcarrier 26 for releasably connecting such sear carrier to the actuatorblock for unitary movement. Also, an upwardly extending arm portion 52provided with an upwardly and forwardly inclining cam `surface 54 and aninclined surface 56 which extends upwardly and rearwardly therefrom.Such hook and arm portions are located above pin 46. A depending lugportion 58 extends from con nector member 48 below pin 46. When hook 49is disengaged from groove 50 and scar carrier 26 and actuator block 24are separated, such hook portion is slidably engaged with the top of thesear carrier rearward of such groove.

Extending upwardly from the front portion of sear carrier 26 is a pairof laterally spaced ears 60 which are drilled to receive a transverseshaft 62 upon which there is mounted for pivotal movement a sear 64.Such sear is provided with a forwardly extending, downwardly facinglatch portion 66 from the front end of which a camV surface 68 extendsupwardly and rearwardly. An overhanging portion V69 projects rearwardlyfrom sear 64 to be engageable with the top side of sear carrier 26 whenlatch portion 66 is parallel with the longitudinal axis of channelmember 14 and whereby such latch portion is permitted to be pivoted awayfrom such longitudinal position only in a downward' direction.

Extending longitudinally through sear carrier 26 is a bore 70 andslidably vmounted therein is a plunger 72 which projects therefromtoengage lug portion 58 of connector 48. A compressible coil spring 74is mounted in'bore 70 forwardly of plunger 72V and is arranged to bearresiliently against such plunger and a lug portion 76 depending fromsear 64 below shaft 62.1Whereby,

connector 48 is pivoted to resiliently press hook portion' l carrier 26for cooperable engagement with arm .portion 52"of connector 48, ashereinafter described, whensear` l carrier 26 is in forwardpositiongblut` to pass'V freely thereby when such -sear carrier is inthe rearward'posi- Projecting from the end of leg portion tlil'isfaVshelf 84 the top of which matinglyengages latch por tion.

tion 66 of sear 64 when hammer 22 is in cock position and sear carrier26 istengaged with pin 40 andis disengaged therefrom when such searcarrier and actuator binds 2,4, are pulled rearwatdly by Lanyard 42, tetheir warmest positions- Operation To fire the firearm in which the.trigger Ymechanisrri of this invention is incorporated, the firearm ischarged by retracting the bolt thereof (not shown), whereby hammer 2K2is p ivotcd to cockl position, winding spring l5. When hammer 22v is incock position, shelf 8d thereon is in full engagement with latch portiond6 of scar 64 with the engagement of overhangingporticn 69; cf. scar64.- against the top of 'Sear carrier 26 preventing the` pivotingof/such sear to unlatch such hammer, and such' latch portion. is pressedforwardly into engegement with suchvshelf through the biasot Spring9againstfactgatcr block 24..

Lanyard 42 is. then. pulled t0 draw actuator block 24 attached theretorearwardly, andas such actuatorV block is joined to Scar Carrier 2,16 bymeans ot ctmnccttnrA 4& Such se'ar carrier is drawn'rearwardly also,disengaging latch portion dofscar dfrom shelf S4A of hammer 22, Whendisengageciy from seal- 64, hammer -22 is biased to fire Position by theWoundsnring 15- During theA initial movement of hammer 2,2?, arm portion82 thereon engages cam surfacev S4y to-cam'mingly pivot connector 48` sothat` hook portion 49i thereof is disengaged from groove 50ct scarcarrier 26. Thus,v Sear carrier 2 6v is disengaged from actuator block24V and free to be returned to normal position against pin 4,6, readytoL relatch hammer 22 by the bias of spring 74. On the ensuing recoil ofthe iirearm boltl (notrshown), fo1lowing the firing of therearm, hammer22 is pivoted thereby, as already explained, to cock positionwith shelt"84 there i eugagingagtsurfacc 68 cftsear 64 to. tiltlatch portiontithere'of downward against thebias of springk 74,permitting such shelfyto pass b y such latch portion for reengagement therewith.

If by chance the operator should release lanyard 42,y permittingactuator blockI 24 to be, returned to forward position against Searcarrier 2,6 before hammer-22 is pivoted'to cock position, arm 5`2 ,willbe moved out, of the Way. of the passing armlportion 82 ofV such hammerYby. the camming engagement thereof with inclinedk surface 56. Whenlanyard 42, isV released, permitting actuator block 2,4y to bebiasedforwardly by, spring 39, hook por.- tion 4,9; of connector 48; ywhichhasbeen slidablyengaged with the, top side of scar carrierZslidSQIWardIyA/to berceivedby groove 50,2111@,therehyfertgagsS-.Searcarrier 2,6110 actuatorY block 24 ready to be pulledfrearwardly bylanyard 42 yto ire anotherround.

From the foregoing it isl clearlyfapp'arentthat there is herein provideda novel, trigger mechanismy of. in -line operaticrxnA which has` a,short trigger pull, is of,l positive neraticnandis. Simple and nlgged in[construction Although a partisularembodimcnt0f the inventive-.has

been described inl detailv here it isvevident thatmanyvariations may be'devised Within.,Y the. Spirit.. and` scope:

grooves therealong, atsear deviceforreleasably holding said hammerinsaid cockposition mounted for slidable movement along said groove, searactuating, means mountedfor slidable movementy alongf said grooverearwardly of said sear device, connectormeansffor releasf, ablyengaging said seardevice toj said scarLA actua-ting means, i ald an armm1; Saidhammerfcamminglyvncoper- Y able said-,connectormeans `fordisengaging said 'sean device from said scar actuator means duringmovement ol" said hammer from said cock position to said fire position.

2. In a firearm having a receiver, a trigger mechanism including ahammer pivotally mounted in the receiver for reciprocation between acock position and a fire position, a channel member fixedly mounted inthe receiver real'- wardly of said hammer and provided with longitudinalgroovestherealong, a Sear device mounted for sliding movement along saidgrooves between a latch position wherein said hammer is releasably heldin said cock position and an unlatch position, means for biasing saidscar device to said latch position, sear'actuator means mounted in saidchannel member rearwardly of said scar device for sliding movement alongsaid' grooves, resilient means for biasing said scar actuator meanstowards said sear device, connector means for releasably engaging saidSear actuator means to saidk sear device whereby said scar device ismovable by said Sear actuator mea-ns to said unlatch position, and`anarm on said hammer cammingly cooperable with, saidV connector meansduring movement of said hammer from said cock position to said tireposition for disconnecting said Sear device from said scar actuatormeans whereby-said scar device is returnableA to said latch position bysaid means for unlatching said hammer when actuated to said cockposition.

3. In a` firearm having a receiver, a trigger mechanism including ahammer pivotally mounted in the receiver forl reciprocation betweenA acock position and a lire position, a sear device mounted in the receiverfor reciprocal longitudinal movement between a latch position whereinsaid hammer is releasably heid by said scar device in said cockpositionandanA unlatchv position, sear actuator means mounted forreciprocal longitudinal movement in the receiver, a spring for biasingsaid sear actuator means toward saidsear device, means for moving said'scar actuator against the bias of said spring, aconncctorv mounted toJvsaid scar actuator means for pivotal movement on a pin transverselytherethrough, said connector being provided with an armhaving acamlsurface and a projecting hook portionV disposed abovcsaid pin and alug portion depending below said pin, `said hook portion being engage,-ablewitlia groove in said seardevice for releasably connecting said scardevice to said scar actuator means, a

coil springmountedV between saidsear device and said lug 'forsimultaneously biasing-said-sear device to said latch position'andisaidhookportion into engagement with said grooye, andanlarmfportionprojecting from said hammerk for engagement with said cam"surface during actuation. from said cock position to said fire-positionfor pivoting said connector to discngagesaid hook frornsaidv groovewhereby saidsear device is disconnected-from, said scar actuator meansfor the return of s aid sear device tosaid latch positionbysaidcoilspring to-relatch said hammer when actuated tosaid cockposition.

4. In a firearm4 having a, receiver, a trigger mecha-- nism, including ahammer pivotally mounted in there ceiver forV reciprocationl between avcock position andA a fire position, a scar; carrier mounted in thereceiver` for reciprocal )longitudinal movement between a forward'positionand a rearward position, a. scar havingl alatchV portion mountedinA said carrierV for pivotal movementv between a'latch-position whereinsaid latch. portion is disposedparallel to theflongitudinal axis of saidscar -carrier and an unlatch'position whereinsaidglatchportionisinclineddownwardly, an overhanging portion eX- meansfor moving said sear actuator against the bias of said spring, connectormeans for releasably engaging said sear carrier to saidrsear actuator,an arm on said hammer cammingly cooperable with said connector means forreleasing said sear carrier from said sear actuator, and spring meansfor simultaneously biasing said carrier to said forward position whenreleased from said sear actuator and said Sear to said latch position.

5. In a rearm having a receiver, a trigger mecha nism including a hammerhaving a leg` portion and an arm portion at right angles thereto, saidhammer being pivotally mounted in the receiver for reciprocation betweena cock position wherein said leg portion extends downwardly and said armportion extends rearwardly therefrom and an upward fire position, ashelf portion extending from said leg portion toward said arm portionparallel with the longitudinal axis of the receiver when said hammer isin said cock position, a Sear carrier mounted in the receiver forlongitudinal movement be tween a forward position and a rearwardposition, a sear having a latch portion mounted to said sear carrier forpivotal movement between a latch position wherein said latch portion isengageable with said shelf portion when said hammer is in said cockposition and said carrier is in said forward position and a downwardunlatch position wherein said shelf portion is passable thereby forengagement with said latch portion, an actuator member mounted in saidreceiver rearwardly of said carrier for reciprocal longitudinalmovement, said actuator being normally biased rby a spring toward saidcarrier, means for moving said actuator against the bias of said spring,a connector rotatably mounted to said actuator for releasable engagementwith said carrier whereby said carrier is movable to said rearwardposition by said ac tuator, said connector being provided with a camportion engageable by said arm portion during movement of said hammerfrom said cock position to said fire posi- Vtion for pivoting saidvconnector to disengage said carrier from said actuator, and spring meanscooperating with said sear and said connector for simultaneously biasingsaid sear to said latch position, said carrier to said forward positionand said connector into engagement with said carrier.

6. In a firearm having a receiver, a trigger mechanism including ahammer provided with an arm portion and a leg portion at right anglesthereto having a shelf projecting therefrom toward said arm portion,said hammer being pivotally mounted in said receiver for reciprocationbetween a cock position wherein said leg portion extends downwardlyandsaid arm portion rearwardly therefrom and an upward lire position, ascar carrier mounted in said receiver rearwardly of said hammer forreciprocal longitudinal movement between a forward position and arearward position, a sear provided with a latch portion mounted forpivotal movement between a latch position wherein said latch portion isengageable with said shelf portion when said hammer is in said cockposition and said carrier is in said forward position and a downwardposition wherein said shelf portion is passable thereby during movementof said hammer to said cock position for latching with said latchportion, an overhanging portion extending from said sear for en- Kgagement with said carrier to prevent the pivoting of said latch portionupwardly away from said latch position, an actuator mounted in saidreceiver rearwardly of said carrier for reciprocal longitudinalmovement, spring means for biasing said actuator forwardly toward saidcarrier, actuating means for pulling said actuator against the bias ofsaid spring means, a connector mounted for pivotal movement on atransverse pin through said actuator, said connector being provided withan arm and a hook disposed above said pin and a lug portion projectingbelow said pin, said hook being receivable by a groove in said carrierfor releasably engaging said actuator thereto, said arm being providedwith a cam surface engageable by said arm portion of said hammer duringmovement thereof from said cock position to said re position forpivoting said connector to disengage said hook from said groove and aninclined surface extending from said cam surface for engagement by saidarm portion of said hammer during movement thereof from said re positionto said cock position for cammingly moving said arm portion out of theway thereof, and a spring mounted between said lug and a dependingportion of said sear for simultaneously biasing said carrier to saidforward position, said sear to said latch position and said hook intoengagement with said carrier.

References Cited in the le of this patent UNITED STATES PATENTS 580,923Browning Apr. 20, 1897 821,922 Burgess May 29, 1906 885,436 Clement Apr.28, 1908

